DRV8320 Datasheet, PDF (38/80 Pages) Texas Instruments – 6 to 60-V Three-Phase Smart Gate Driver

DRV8320, DRV8320R
DRV8323, DRV8323R
SLVSDJ3 – FEBRUARY 2017
www.ti.com
Figure 34 shows the structure of the open-drain output pins nFAULT and SDO. The open-drain output requires
an external pullup resistor to function properly.
DVDD
STATE
No Fault
Fault
STATUS
Inactive
Active
R_PU
OUTPUT
Active
Inactive
Figure 34. Open-Drain Output Pin Structure
8.3.4 Low-Side Current-Shunt Amplifiers (DRV8323 and DRV8323R Only)
The DRV8323 and DRV8323R integrate three, high-performance low-side current-shunt amplifiers for current
measurements using low-side shunt resistors in the external half-bridges. Low-side current measurements are
commonly used to implement overcurrent protection, external torque control, or brushless DC commutation with
the external controller. All three amplifiers can be used to sense the current in each of the half-bridge legs or one
amplifier can be used to sense the sum of the half-bridge legs. The current shunt amplifiers include features such
as programmable gain, offset calibration, unidirectional and bidirectional support, and a voltage reference pin
(VREF).
8.3.4.1 Bidirectional Current Sense Operation
The SOx pin on the DRV8323 and DRV8323R outputs an analog voltage equal to the voltage across the SPx
and SNx pins multiplied by the gain setting (G_CSA). The gain setting is adjustable between four different levels (5
V/V, 10 V/V, 20 V/V, and 40 V/V). Use Equation 3 to calculate the current through the shunt resistor.
I
V_VREF
2
V_SOx
G_CSA u R_SENSE
(3)
R2
R3
R4
SOx
R6
V_CC
V_REF
0.1 …F
½
+
±
R5
R1
±
R1
+
R2
R3
R4
I
SPx
SNx
R_SENSE
R5
Figure 35. Bidirectional Current-Sense Configuration
38
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